Improvement in operating window-blinds



NTTnn STATES PATENT Ormea3 HENRY SMITH, OF SALEM, MASSACHUSETTS.

IMPROVEMENT IN OPERATING WINDOW-BLINDS.l

Specification forming part of Letters Patent No. 52,332, dated January30, 1866.

others of a similar class, together with such.

parts as I claim and desire to have secured to me by Letters Patent.

The object of the present invention is to provide a balance to thevarying power of a coiled spring in such a manner that the power givenout by the spring will be equalized, so that in unwinding the springwill give out the same power When it is nearly unwound as when it istightly coiled.

This invention in the present application for Letters Patent is appliedto the purpose of providing an equal balance forla curtainfixture, andis represented in the accompanying plate of drawings, of which- Figure 1is a vertical longitudinal section, and Fig, 2 a horizontal longitudinalsection, of my improved device connected with a windowshade.

c a a in theV drawings represent the box or frame-work of a window, inwhich is inserted my apparatus, which consists of a gear-Wheel, l) b,upon the face of Which is formed a volute gear, c c, the teeth of whichare arranged in the shape of a volute, as shown by the holes d d d.Attached to the volute gear c o is a shaft, e e, which turns instandards formed by the front and rear plates of the case or frame f fof the apparatus.

Formed on one end of a shaft, g g, is a pinion, h h, with circularpointed teeth, which engage with the volute gear c c and operate thesame by means of the power imparted to it by a coiled spring,t' z',inclosed in a case, 7c 7c, one end of the spring t t' being fastened tothe end ofthe shaft g g, which passes through the case 7c It.

Formed on the case 7c k and attached to the l shaft g g by standards ll, which form bearings for the shaft g g, is a slide, m m, formed with aslot, u n, which travels on a pivot, o, for the purpose of moving backand forth the shaft g g and case lc 7c to suit the position of thepinion h h, which works in the volute gear c c.

Engaging with the gear b b on the periphery of the volute gear c c is apinion, p p, attached to a shaft, q q, the outer end of which shaft q isformed square to receive one end of a shade-roller, r r, and turns in abearing, s s, formed by the end of the plate or frame f f. A pivot, t,is formed on the other end of the curtain or shade roller r r, and turnsin a bearing formed by the standards a a attached to the opposite sideof the window-frame a a.

A slide, t, in the upper part of the standards u u lits over the pivot tand serves to hold it in place when the roller r r is adjusted. When theslide o is removed from the standards a a the pivot t can be easilydetached therefrom and the roller r r removed.

By the foregoing description, reference being made to the drawings, itwill be seen that by drawing down the shade w Lo attached to the rollerr r, which is tted onto the square end of the shaft q q, the pinion ppis revolved, and thereby turns the volute gear c c, with whose outergear, b b, the said pinion p p engages. The volute gear c c in turnoperates the pinion h h and shaft g g, to which it is attached, therebycoiling up the spring t t', fastened to one end of the shaft g g andinclosed in the case k lo. volves it draws laterally the pinion It h andslide m m toward its center, thus giving the pinion h h more and moreleverage in its relation to the pinion p p, and thereby compensating forthe increasing power of the spring i i as it is coiled up. The volutegear c 0 and its pinion h h are arranged in such a manner with regard tothe spring i i that the force exerted by the weight of the shade w wjust balances the spring t t',. and consequently the shade lw fw remainsin any position in which it is placed. When the shade fw-w is raised orits weight relieved the action of the spring il 'i upon the shaft g gcauses the pinion l1. h to revolve the volute gear c c, which turns theshaft q q connected with the roller r r, and thereby winds up the shade'w w attached to the-roller r r.

As the volute gear c o re-` Having thus described my improvements, 2.The combination of the volute gear, travshall state my claim as follows:cling pinion, spring, and shade-roller, for the What I claim'as myinvention, and desire purpose of controlling the power of the spring,`to have secured by Letters Patent, isin its action upon the said roller,as described.

l. Gompensating for `the increased or diminished power of a coiledspring in its various degrees of tension by means of a pinion working ina scroll-gear or volute toothed rack, whether said rack is wound on aplane surface or on the periphery of a cone7 substantially as described.

HENRY SMITH.

Witnesses:

OLWER C. SMITH, M. B. MANSFIELD.

